Junxi Cheng, Chang Liu, M. H. Liu, Hewei Yang, Qihua Sun, Ting Li, Zhaofeng Wu
Ethylene glycol (C 2 H 6 O 2 ) is a widely used yet toxic compound, requiring energy-efficient detection methods beyond prevalent high-temperature sensors. Here, an imine covalent organic framework (COF-TPC) was synthesized at room temperature (RT) using 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (Tp) and 2,5-dichlorobenzene-1,4-diamine (Pa-Cl) as ligands, with acetic acid as a catalyst. The structure−property relationship was investigated by controlling Schiff base reaction time (1−70 h), yielding four sensors (COF-T-30, COF-T-40, COF-T-50, and COF-T-60) for testing. Gas sensing data revealed that the COF-T-50 sensor exhibited a response of 6107% to 500 ppm C 2 H 6 O 2, significantly outperforming the other sensors. It also exhibited outstanding selectivity toward C 2 H 6 O 2 among 13 gases, along with excellent repeatability and moisture resistance. DFT calculations elucidated the adsorption mechanism and the origin of its exceptional selectivity. This work provides a new approach for rapid, stable C 2 H 6 O 2 detection using COFs, expanding their application scope.